Table of Contents
Roseberg, R.J. 1996. Underexploited temperate industrial and fiber crops. p.
60-84. In: J. Janick (ed.), Progress in new crops. ASHS Press, Alexandria,
Underexploited Temperate Industrial and Fiber Crops
Richard J. Roseberg
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- FIBER FLAX
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Crop Status
- Likely Commercial Production Areas
- Raw Material and Products
- Competing Sources
- Crop Status
- Likely Commercial Production Areas
- SUNN HEMP
- HEAVY METAL HYPERACCUMULATORS
- OTHER POTENTIAL CROPS
Successful temperate new crops must either fit well into the rotation of
established food, feed, or fiber crops, provide a product that is relatively
more valuable than the current crop, or be better suited to growing on a given
area. Proximity of growers to potential processors (who manufacture the
refined product) is key to economic advantage for the new crop over prior raw
material sources. In the case of arid industrial crops, the issues of survival
in a harsh climate and the cost of water are paramount, while in the higher
latitude temperate zones the constraints are frost tolerance, length of growing
season, crop response to daylength, water requirement (rain-fed or irrigated),
and weather patterns during harvest.
This paper examines the current status of several potential crops with an eye
toward their requirements for success in temperate zones. Crops that are
reaching or have reached active crop status include meadowfoam, fiber flax, and
kenaf. Crops that are very promising, but require some further breeding,
agronomy, or processing research include lesquerella, cuphea, euphorbia, and
vernonia. Crops that are intriguing, but need more study to define their
potential and value include grindelia and hesperaloe. Other potential crops,
including those with application only in specific situations or those having
received limited study and commercialization efforts are also briefly
The activity level for each crop is described using four new crop research and
development categories put forth by L.J.M. van Soest (1993): I Plant
exploration and evaluation; II Crop improvement (including plant breeding and
agronomy; III Processing and application research; and IV Marketing,
commercialization, and utilization. Estimating the crop's value or return to
the farmer was difficult, and this difficulty increased the further away the
crop was from commercialization. However, crop values were calculated using
comparisons with currently available raw materials and estimates of possible
differences in value.
The key early development for meadowfoam (Limnanthes species,
Limnanthaceae) came out of the extensive USDA efforts of the late 1950s and
early 1960s when many plant species were analyzed in a search for novel
compounds. Out of these efforts at the National Center for Agricultural
Utilization Research (NCAUR) laboratory, it was first recognized that 94% of
the fatty acids in meadowfoam (Limnanthes douglasii R. Br.) seed oils
had chain lengths of 20 carbon atoms or longer (Earle et al. 1959).
Identification of these previously unknown long-chain fatty acids was made soon
after (Smith et al. 1960; Bagby et al. 1961). Later interest shifted to
Limnanthes alba Benth. due to its improved agronomic characteristics
such as increased seed retention, upright growth habit, and plant height. Seed
retention is no longer a problem. In fact, the cultivar Floral is considered
difficult to thresh by growers. L. alba contains high levels of the
same fatty acids as L. douglasii (Miller et al. 1964). Results of early
agronomic and breeding work have been summarized by Jolliff et al. (1981).
Results from additional crop and oil analysis were summarized by Purdy and
Within the past two years the consistent involvement of industry, specifically
Fanning Corp. (Chicago), has greatly stabilized the supply-demand situation,
creating a steadily increasing demand. This is unlike the whipsawed supply,
demand, and price history of the 1980s. Cooperation between the Oregon
Meadowfoam Growers Association (OMGA), Oregon State Univ., Fanning Corp., and
USDA-NCAUR has improved the coordination between crop research, product
research, grower contracts, crop price, and crop area expansion.
Meadowfoam seeds contain about 25% oil, 95% of which is made up of C:20 or C:22
monoene or diene fatty acids (Kleiman 1990). Such specificity in long chain
fatty acids is rare in nature. Such fatty acids could be used in cosmetics
(moisturizers, soaps, hair care), specialty lubricants and polymers (Purdy and
Craig 1987; Bosisio 1989; Carlson et al. 1992).
Meadowfoam oil naturally occurs in the form of triglycerides. However, reports
have described how C:40-C:44 wax esters similar to those of jojoba
[Simmondsia chinensis [Link] Schneid.] and sperm whale oils could be
produced from meadowfoam oil by reducing fatty acids to alcohols and then
forming esters using unreacted fatty acids (Miwa and Wolff 1962; Miwa 1972;
Nieschlag et al. 1977). Despite statements to the contrary (Cook 1971),
meadowfoam oil is not a substitute for sperm whale oil. Unmodified meadowfoam
oil is structurally quite different from sperm whale oil, and jojoba would
appear to be a better source of these compounds (Kleiman 1990).
Long chain fatty acids are currently produced from high erucic acid rape seed,
crambe seed, and for some applications, fish oils (Jolliff et al. 1981; Purdy
and Craig 1987). However, the erucic acid (C22:113) from crambe and
rape seed is chemically different than the three other fatty acids
(C20:15, C22:15, and C22:25,13) that make up
about 85% of meadowfoam oil (Purdy and Craig 1987; Kleiman 1990).
Meadowfoam research and development efforts in the U.S. currently include
categories I-IV. The only active crop research program is at Oregon State
Univ. in cooperation with the OMGA and Fanning Corp. Product development is
ongoing at the USDA-NCAUR in Peoria, Illinois, at Fanning Corp., and elsewhere.
Fanning Corp. is leading market development efforts. With the current
industrial demand remaining steady, the crop area is increasing from about 900
ha in 1995 to an estimated 2400 ha in 1996 in Oregon's Willamette Valley.
In Oregon, seed yields typically have ranged from 600-1200 kg/ha with current
cultivars. Given the oil content and fatty acid composition, 1200 kg/ha would
be worth $315/ha at rapeseed prices. However, the unique chemistry of
meadowfoam oil has prompted recent contracts for $1.10/kg seed, resulting in a
crop value of about $1320/ha at the high end of the normal yield range.
The requirement for insect pollination has probably limited yields in
commercial fields. Research plots can be saturated with honeybees, but in
typical commercial fields only two of the five potential seeds in each flower
matures. Thus, development of auto-fertile cultivars should improve yield.
The range of adaptation should be further explored as new cultivars are
developed. Little is currently known about range limitations.
Meadowfoam growth on clay soils is usually acceptable, and in fact this
characteristic has been one of the main reasons for its development in western
Oregon. While native to western Oregon and northern California, meadowfoam
should be well adapted to areas that have cool soils at planting, cool and
moist weather during vegetative growth, and warm, dry harvest weather. In
addition to the Willamette Valley in Oregon, such areas could include western
Washington, northern Europe, New Zealand, and parts of southern Australia and
Flax [Linum usitatissimum L., Linaceae] is not a new crop. There are
six references to women and flax in the Bible, indicating that flax spinning
and weaving were household industries in antiquity. The center of origin of
flax is thought to be in the Near East, but the exact area is a topic of
debate. A highly selected cultivar dating from 5500-5000 BC was found in Iran
(Dempsey 1975). Earlier flax types have been found both in Egypt and
Switzerland. By 4000 BC the Egyptians had a highly developed flax industry.
Other nations of the area also developed flax, and its domestication was well
established in western Europe by the time of Charlemagne (742-814).
The first mechanized method for spinning flax yarn was developed in France.
Between 1810 and 1820 Philippe de Girard was issued six patents relating to
this new technology (Dempsey 1975). To maintain maximum fiber length and
quality, flax is pulled from the ground at harvest, rather than cut. Until
World War II flax was mainly pulled by hand. Since then this extremely labor
intensive process has been mechanized, first by tractor-drawn machines, and
then by self-propelled pullers. These machines, along with specialized turners
and deseeders, were mainly developed in western Europe in the 1950s and 1960s,
improving upon earlier U.S. developments during WWII and soon after. These
technologies have greatly increased the speed and ease of harvest. They have
also improved the utility of the inexpensive dew-retting process, whereby the
pulled flax fiber is separated from cellulose and other stem parts by bacterial
action in the presence of water (the dew) in the field. Field equipment and
modern processing plant equipment have been further developed in western Europe
during the 1980s and 1990s, allowing greater capture and separation of all
classes of flax fibers while improving worker safety conditions (D. Ehrensing
1995, pers. commun.). Thus fiber recovery is currently about 25% of total
biomass yield, up from about 20% forty years ago. Flax breeding was very
active in the United States during the 1930s and until the 1950s, but ceased by
the early 1960s (Calvert and Marks 1995). However, cultivar development has
continued in Europe, especially in France, The Netherlands, and Belgium.
In the 1940s flax was grown on up to 7300 ha in Oregon (Hurst et al. 1953).
The reintroduction of European flax after the end of World War II, the increase
in cotton use in textiles, and the development of petroleum based fibers such
as nylon combined to essentially eliminate the Oregon flax industry by the mid
1950s. Interest has recently been revived, mainly due to restrictions on
stubble burning from grass seed production that have created problems for
farmers in terms of weed control, insect, and disease cycles. Grass seed
production occupies over 175,000 ha annually in Oregon, mainly in the
Willamette Valley, (U.S. Dept. of Commerce 1993), and Oregon routinely produces
over 90% of the world's perennial ryegrass (Lolium perenne L.),
orchardgrass (Dactylis glomerata L.), and bentgrass (Agrostis
palustris Huds.) seed. Because flax is a dicot it would provide a break in
disease cycles and allow use of alternate herbicides while providing a cash
crop for grass seed growers.
Although all flax cultivars produce fiber in the stems and oil (linseed) in the
seeds, fiber flax cultivars have been bred and selected specifically to produce
large quantities of very long, high quality fiber, with oil production only a
secondary consideration. Flax produces fibers of varying length. The longest
fibers can be used in making fine linens for clothing, draperies, and
furniture, medium fibers have been used for canvas and geotextiles, while short
fibers have been used for paper and sacking.
Fibers from oilseed flax, jute (Corchorus capsularis L.), sisal
(Agave sisalana Perrine), hemp (Cannabis sativa L.), cotton
(Gossypium hirsutum L.), and wood species are currently used for some of
the applications suited to fiber flax. However, the high strength and quality
of flax fiber makes it superior than other sources for some applications, such
Fiber flax research and development efforts in the United States currently
include categories I-IV. In 1993 flax was grown for fiber in Russia (335,000
ha), Ukraine (127,000 ha), Belarus (120,000 ha), China (93,000 ha), and France
(50,000 ha) (FAO 1994). Some fiber from oil seed flax production in Canada and
northern United States (especially North Dakota) has been used recently in
cigarette paper production (P.M. Carr 1995, pers. commun.).
Fiber yields in western Europe have recently been in the range of 1500-2000
kg/ha, while yields in Russia and eastern Europe have usually been less than
half of those amounts (FAO 1994). This may have been due to use of oil
varieties as well as poorer crop technology or management. Oregon farm fiber
yields in 1995 were about 1200 kg/ha. Oregon statewide average yields from
1925 through 1951 ranged from 1.3 to 5.1 t/ha dry matter (or about 260 to 1020
kg/ha fiber) (Hurst et al. 1953).
Flax fibers that have been separated from the straw (skutched), but not combed,
typically have ranged in value from $ 0.20-3.00/kg, with the longest fibers
commanding the higher price (van Gelder et al. 1993; FAO 1994). Due to recent
high demand, prices for short fibers have only been slightly less than those
for long fibers (D. Ehrensing 1995, pers. commun.).
Due to its long history of development, flax has few remaining problems, both
in terms of agronomy and processing. The main hindrance to recommercialization
in Oregon is lack of a processing plant. Estimated capital costs are $1.0
million (including the specialized field equipment) to process only short
fibers, or $1.5 million to process the more valuable long fiber separately (D.
Ehrensing 1995, pers. commun.).
Markets would likely expand if improved technology to use the strong flax
fibers in combination with cheap, weaker fibers were developed. Flax could
conceivably be mixed with excess grass seed straw or softwood fiber in
composite boards or high quality papers, with cotton or polyester in clothing,
or to reinforce plastics and composite materials.
Fiber quality is enhanced by cool, moist spring weather followed by warm
summers, with sufficient dew or light rain for field retting. Current
production areas in northwest and eastern Europe are well-suited to fiber flax
production, as are western Oregon and part of Michigan. Flax will grow in
other climates, but fiber yield and quality are usually much poorer. For
example, the oilseed flax production areas in north-central United States and
south central Canada change from cool to hot weather rapidly, resulting in
poorer fiber quality. Fiber flax production in the United States seems most
likely to succeed in the Pacific Northwest due to its high fiber quality and
the concentration of industry already producing fiber-based products there.
Kenaf (Hibiscus cannabinus L., Malvaceae) has long been cultivated,
probably as early as 4000 BC in Africa. Early research in the U.S. on using
kenaf as a substitute for jute was begun in the 1940s due to the supply
disruption from the Far East during World War II. This work continued into the
1950s, when more applied efforts, as part of the USDA Search for New Pulp
Fibers program, began and continued into the 1970s (Taylor 1993). Details of
this early work were well summarized by Dempsey (1975), and White et al.
(1970). In 1977, the Peoria Journal Star was printed on kenaf
newsprint, thus demonstrating the development of agronomic and processing
technology for kenaf newsprint production. Official USDA and land grant
university involvement in kenaf research was on hiatus from 1977 until 1986,
when the Kenaf Demonstration Project was begun (Kugler 1988). In the meantime,
several private sector efforts continued to demonstrate kenaf newsprint
technology development, including the printing of several newspapers on kenaf
newsprint at various times from 1977-1987 and the construction of a 200 t/day
commercial pulp mill in Thailand that utilized kenaf fiber (Taylor 1993).
With the activation of the Kenaf Demonstration Project, many improvements in
agronomic, processing, and newsprint production and use were made, building on
the successes of the earlier efforts. An important commitment was the addition
of Dr. Charles Cook to the USDA-ARS Weslaco, Texas station. Dr. Cook's primary
research emphasis has been kenaf breeding and agronomy, and he has developed
selections of kenaf having improved tolerance of root knot nematodes and
associated pathogenic soil fungi (Cook and Mullin 1994). These pests have been
significant problems in areas where kenaf was part of a cotton rotation.
Development of effective harvesting, material handling, and fiber separation
equipment was a breakthrough made primarily by the efforts of Harold Willett
(Taylor 1993), although other separation designs also have been developed (Chen
1994). Summaries of developments since about 1987 have been published (USDA
1990; Taylor 1993: and D. Kugler elsewhere in this volume).
The kenaf plant contains moderately long fibers in its outer stem and short
fibers in its core. The outer stem (bark) makes up about 35%-40% of the stem
weight, with the inner stem (core) containing the remaining 60%-65%. The fiber
content of kenaf bark is about 50%-55%, increasing with plant population
density, while the less valuable short fibers make up about 45%-50% of the
inner core (Clark and Wolff 1969; Wood et al. 1983). Traditionally, the fiber
has been used on several continents for rope, sacking, twine, and matting.
However, its value will be greater if used for newsprint, carpet backing, and
mixed into composite materials for boards or other structural materials (Taylor
and Kugler 1992; Taylor 1993). The inner fiber has absorbent qualities that
potentially could be used in products such as oil absorbents or poultry litter.
Attributes of the kenaf plant were described in great detail by Dempsey (1975).
For coarse fiber (lower value) applications, kenaf must compete with imported
tropical monocots, chiefly jute. The higher value newsprint market in the
United States is huge, and imports accounted for as much as 7.5 million tonnes,
worth $4.5 billion in recent years (USDA 1993). In this market kenaf must
compete with wood pulp. Increasing amounts of newsprint have been imported
into the United States (up to 60% of consumption recently), mostly from Canada.
Kenaf research and development efforts in the United States currently include
categories I-IV. Kenaf was grown on about 1660 ha in the U.S. during the early
1990s (USDA 1993). However, plans have been in place for several years to
build a pulp mill requiring up to 2000 ha of kenaf mixed with recycled
newspapers to produce 85 t newsprint per day (Taylor 1993). Construction has
been delayed due to insufficient financing, but recent increased newsprint
costs should tend to make such an enterprise more viable. The intent is still
to complete the project, but details on timing and size are not yet public (C.
Taylor 1996, pers. commun.). The potential area of U.S. kenaf cultivation
could be as great as 0.4 to 2.0 million ha if the current upward trends in
paper demand and price continue (USDA 1993; Stone 1995). Worldwide, kenaf was
produced on about 200,000 ha, with major producers including China,
Commonwealth of Independent States, Thailand, Cuba, India, and Mexico (FAO
Kenaf yields vary widely, not surprising given the range of areas where it has
been grown and level of crop inputs. As plant density increases, stem
diameters tend to decrease, but the proportion of bark tends to increase.
However, the interactions between local climate, crop management, cultivar,
stand density, and plant mortality make it difficult to predict stem and fiber
yield without field testing (Clark and Wolff 1969; Higgins and White 1970;
White et al. 1970; White et al. 1971; Dempsey 1975; Campbell and White 1982;
Bhangoo et al. 1986; Scott et al. 1989). Commercial yields in the range of 9
to 22 t/ha biomass dry weight have often been reported. The higher yields were
generally realized when growing conditions improved, typically as one moves
from dry, high latitude locations to humid, lower latitude sites. In well
adapted areas, such as the southeastern U.S., kenaf has typically yielded three
to five times more fiber per year than southern pine, the typical pulping raw
material source in that area (Wolff 1964; USDA 1993). Testing at several
higher latitude temperate sites suggested that the adaptation of kenaf can
change quite rapidly with a fairly small climatic change (White et al. 1970;
Lauer 1990; Evans and Hang 1993). Results from a 1994 kenaf trial in southern
Oregon showed this effect. The cultivar G4, although planted four weeks later
than ideal, yielded an average 12.0 t/ha stem dry weight in the Rogue Valley,
compared to 6.3 t/ha in the Willamette Valley (320 km to the north). Four
cultivars that were planted four weeks before G4 yielded from 14.6 to 18.1 t/ha
in the Rogue Valley.
Kenaf fiber in Thailand (where commercial kenaf pulping operations have been
ongoing since 1981) were recently valued at $ 364/t (FAO 1994). To compete
with wood as a pulp source in the northwestern U.S., where wood fiber is still
relatively plentiful, a kenaf crop would generally sell in the range of
$55-88/t (stem dry weight). For a yield of 13.5 t/ha and a price of $65/t, a
grower would gross $878/ha. Part of the value of kenaf is due to the fact that
pulping requires 15%-25% less energy and less chemical inputs than wood pulping
(USDA 1993; Taylor and Kugler 1992).
An economic analysis for the Rio Grande Valley of Texas indicated that kenaf at
$44/t would compare favorably to other crops commonly grown in that area (Scott
and Taylor 1990). The overall demand for paper has continued to increase since
that time. Pulp prices per tonne have rebounded from a low value of $453 in
1993 to an estimated $890 for 1995 (Brown 1995). Most analysts suggest that
the dramatic price increases have been due to a combination of increased paper
demand, unchanged production capacity, and increased cost and/or reduced
availability of wood fiber, especially from federal timber lands in the U.S.
(Hagler 1995; Stone 1995; Anon. 1995). These trends in paper demand and wood
fiber availability are not expected to change. Thus, it appears that there
could well be an increasing demand for quality paper fiber from non-wood
sources, such as from kenaf.
Storage and handling of annual crops like kenaf that are used in year-round
manufacturing has always been somewhat of a problem. The problem is
exacerbated if weather conditions or rotation requirement prevent the grower
from leaving the crop standing in the field during the fall and winter after
harvest. Also, while extended "vertical storage" in the field improves
handling logistics, it also prevents use of the leaves as a forage (unless the
plant tops were somehow harvested earlier in a separate operation). While
ratios and procedures for using kenaf fiber in mixtures with other materials
has been worked out in some cases (i.e. recycled newspapers for newsprint
production), mixing and processing kenaf with materials such as straw, flax
fiber, wood, and synthetics for composite board or other structural materials
still need to be determined and optimized to broaden the applications for
kenaf. Germplasm evaluation and cultivar development need to be continued,
especially in terms of improved pest resistance and adaptation to higher
latitudes (where summer days are longer, but seasons are shorter). Until
recently, unfavorable economics had hindered the development of the kenaf
industry in the United States, but research on the forage value of leaves,
concurrent uses of both types of fiber produced, and increasing demand for
fiber for all applications should improve the economic conditions affecting
Kenaf has been grown in many areas, but highest yields have generally been
observed under the following conditions: Warm soil and air (mean daily air
temperatures between 22° and 30°C), sufficient moisture (monthly
precipitation of 90-275 mm), fairly high relative humidity (65%-85%), a long
frost free season, and fairly well drained soil which may otherwise vary
greatly in texture and chemistry (Dempsey 1975). Good fertility contributes to
higher yields (White et al. 1970; Dempsey 1975; Bhangoo et al. 1986). Kenaf
was found to be moderately tolerant to saline irrigation water (Francois et al.
1990). Growing kenaf under irrigation modifies some of the general
requirements listed above. Thus traditional growing areas in Asia, India, and
the Caribbean/Central America should continue and new or increased production
should be achievable in the southeast, southwest, central, and parts of the
western U.S., as well as northern Australia, Africa, parts of South America,
and southern Europe.
The key early development for lesquerella (Lesquerella species,
Brassicaceae) came out of the extensive USDA efforts of the late 1950s and
early 1960s when many plant species were analyzed in a search for novel
compounds. Out of this effort it was first recognized that Lesquerella
lasiocarpa seed oils contained a high concentration of a hydroxyeicosenoic
acid (Miwa et al. 1960). The structure of this C20:1-OH hydroxy fatty acid
(HFA) was soon identified and given the trivial name of lesquerolic acid (Smith
et al. 1961). Examination of 14 Lesquerella species showed that most
had high concentrations of lesquerolic acid, while two species contained high
levels of a hydroxyoctadecenoic acid (Mikolajczak et al. 1962). The structure
of this C18:2-OH hydroxy fatty acid was soon identified and given the trivial
name of densipolic acid (Smith et al. 1962). The relationship between native
habitat and predominant HFA was recognized by Barclay et al. (1962), who noted
that species native to the western U.S. usually had high concentrations of
lesquerolic acid, while those native to the eastern U.S. had high
concentrations of densipolic acid. However, Lesquerella auriculata, a
native of Texas and Oklahoma, has seed oil with high concentrations of C20:2-OH
(auricolic acid), similar in structure to densipolic acid, but having two
additional carbons on the carboxyl end of the molecule (Kleiman et al. 1972).
Based on morphological and agronomic characteristics, Lesquerella
fendleri (Gray) Wats., a native of the southwestern U.S., was considered
the most likely candidate for domestication (Barclay et al. 1962; Gentry and
Barclay 1962). Early agronomic, germplasm collection, and selection studies
were summarized by A.E. Thompson (1988).
The HFAs found in high concentrations in the seed oil of several
Lesquerella species could be used in producing specialty lubricants,
heavy duty detergents, inks, and coatings due to the special properties of HFAs
compared to other fatty acids, including higher viscosity and reactivity,
caused by the presence of the hydroxyl group (Roetheli et al. 1991). Recent
research has identified their utility in manufacture of plastics, additional
coatings, extruded closed cell foam, facial soap, and cosmetics (Roetheli et
al. 1991; Arquette and Brown 1993; Carlson et al. 1993; Thames et al. 1993a, b,
Castor (Ricinus communis L.) oil contains the HFA ricinoleic acid
(C18:1-OH). In recent years about 45,000 t (worth about $45 million) of castor
oil are imported annually to the U.S. as its primary source of HFA. Because of
this dependence on imports and the importance in certain applications, HFAs
have been classified as a strategic material by the U.S. government. Because
the chain length of lesquerolic acid is two carbons longer than ricinoleic
acid, chemical reactions may provide more useful compounds than those from
castor oil, such as the basic compound needed for nylon 1212 synthesis, whose
current raw material source is petroleum (Kleiman 1990). The presence of two
double bonds in densipolic and auricolic acids suggest their greater ability to
undergo chemical reactions resulting in useful industrial materials. The low
toxicity and low potential for irritation by lesquerella oil (unlike castor
oil) suggests initial development in the high value cosmetics industry in
products such as lotions, hair conditioners, and lipsticks (Arquette and Brown
Lesquerella research and development efforts in the U.S. currently include
categories I-III. The crop has not been grown commercially, but for several
years research-funded seed increases of L. fendleri have been contracted
with growers in Arizona, New Mexico, and Texas, totalling 16-48 ha annually.
Based on plant morphology and limited experience with harvesting of wild stands
in west Texas, Gentry and Barclay (1962) estimated seed yields of unimproved
germplasm could exceed 1100 kg/ha. In more recent large field trials, seed
yields in Arizona have often been between 500-1100 kg/ha, but between 1200-1800
kg/ha in small plots (Thompson et al. 1989; Thompson and Dierig 1988). In
southwest Oregon, plot yields have generally been between 450-1000 kg/ha.
L. fendleri seed typically contains about 25% oil of which 55%-60% is
lesquerolic acid (Barclay et al. 1962; Mikolaczak et al. 1962). Castor seeds
typically contain about 50% oil, of which about 85% is ricinoleic acid (Atsmon
1989). Between 1972 and 1990 castor oil prices ranged between a low of
$0.51/kg in 1972 to a high of $1.60/kg in 1984, but castor oil prices have
fluctuated dramatically, even within a single year (Roetheli et al. 1991).
Based on these prices, calculated lesquerella seed value would be between $0.11
and $0.15/kg. If the seed yield were 1000 kg/ha, lesquerella crop value would
range from $110 to 150/ha. However, lesquerella oil may be more valuable than
castor oil due its applications in high value products such as cosmetics.
Recent projections of seed value by potential industrial users have been in the
range of $ 0.33 to 0.40/kg for improved seed containing 35% oil (Brown, 1994).
Initial commercialization of lesquerella is dependent on developing such high
value uses (Glaser et al. 1992; Arquette and Brown 1993).
Lesquerella fendleri is the species receiving the most research effort.
Other species have been examined only at the category I and II level
(exploration and crop improvement), but could also be valuable crops for
several reasons. Some species produce seeds several times larger than L.
fendleri (Barclay et al. 1962; Mikolajczak et al. 1962; Thompson 1988).
Presumably, larger seeds would be easier to handle and possibly result in
greater oil yields. Some species that produce densipolic or auricolic acid,
unlike L. fendleri which produces lesquerolic acid, are native to areas
outside the southwestern U.S., and thus may be adapted to production in these
other locales. Some are perennials, and could be suitable for topography and
cropping systems different than those that appear optimal for L.
In two years of small plot studies in southwestern Oregon, L.
grandiflora (lesquerolic acid type) plants grew well, were slightly larger
than L. fendleri, and produced impressive amounts of seed. Small plots
of L. perforata (densipolic acid) and L. auriculata (auricolic
acid) have grown and yielded fairly well. L. purpurea and L.
pinetorum (both lesquerolic acid) germinated but produced little or no
seed. Plantings of L. angustifolia, L. engelmannii, L.
argyraea, L. gordonii, L. gracilis, L. lasiocarpa,
L. ludoviciana, (all lesquerolic acid), L. densipila, L.
lyrata, and L. stonensis (all densipolic acid) failed to germinate,
but the age of the seed (1972) probably had more effect than any differences in
adaptation. Plantings in 1995 using several accessions (recently collected by
D. Dierig) of L. douglasii (a perennial, lesquerolic acid type native to
the Pacific Northwest) may further elucidate the cropping feasibility of
species other than L. fendleri if grown in adapted regions.
Because honey bees tend to very active in lesquerella plantings, it has been
assumed that bee pollination enhances yield, although the degree to which
insect pollination is required is not well understood. The generally lower
yields seen in larger fields may be partially due to the difficulty and/or
expense of achieving high bee densities and maximum seed set (Dierig and
Thompson 1993). Thus, the successful domestication of lesquerella may, like
meadowfoam, require the elimination of its insect-pollination requirement.
Breeding work to increase oil and HFA concentrations should increase seed
Plant establishment has been a problem with lesquerella, due to its tendency
toward seed dormancy and weak seedling vigor. Cultural practices that improve
germination and stand establishment have been developed at New Mexico State
Univ. (J. Fowler 1995, pers. commun.). Due to lesquerella's slow initial
growth habit, competition with weeds has been a serious concern. However,
several potential herbicides are good candidates for registration (Roseberg
1993; Foster et al. 1996; Roseberg 1996a), and experimental registration has
been pursued in Arizona, New Mexico, and Texas (M. Foster 1995, pers. commun.).
Additional agronomic and breeding research on L. fendleri is ongoing at
this time, mainly by scientists in Arizona (D. Ray, D. Dierig, J. Nelson, W.
Coates, J. Brown, D. Hunsaker), New Mexico (J. Fowler), and Texas (M. Foster).
Oil and gum analysis, processing, and product development research is ongoing
at the USDA-NCAUR laboratory in Peoria, Illinois (T. Abbott, K. Carlson, and
others), University of S. Mississippi (S. Thames), and scientists at Mycogen
Corp., Lubrizol Inc., and International Flora Technologies (J. Brown and R.
Lesquerella, especially L. fendleri and the other lesquerolic acid
types, seem well adapted to semi-arid or arid locations. Native stands of
L. fendleri are typically found in well drained, calcareous soils
(Gentry and Barclay 1962). Likely production areas may include the southwest
and south-central U.S., western Australia, northern Argentina and Chile, and
northern Africa. L. grandiflora and L. douglasii may be adapted
to parts of the western U.S. and southern Europe.
The key early development of cuphea came out of the extensive USDA efforts of
the late 1950s and early 1960s when many plant species were analyzed in a
search for novel compounds. Out of this effort it was first recognized that
seed oils from certain Cuphea species (Lythraceae) contained high levels
of several medium chain triglycerides (MCTs), but that the specific dominant
MCT varied with species (Earle et al. 1960; Wilson et al. 1960; Miller et al.
1964; Litchfield et al. 1967). Later studies showed that many Cuphea
species contain high levels of various MCTs (Wolf et al. 1983; Graham and
Kleiman 1985). An excellent summary of the genus Cuphea, including
botany and early work in seed oil analyses, was written by Graham (1989).
It was reported at the First National Symposium on New Crops in 1988 that two
major barriers to the domestication of cuphea were seed dormancy and seed
shattering (Knapp 1990). Because seed shattering and indeterminate flowering
both had been universally present in cuphea, it was impossible to harvest a
significant percentage of the seed with practical field equipment. Seed
dormancy has been reduced by use of C. lanceolata, whose selections
contain non-dormant traits, in interspecific hybridization with C.
viscosisima. The C. viscosisima phenotype exhibits desirable
agronomic characteristics due to its moderate plant size, good seed size, and
self-fertile behavior (eliminating the need for insect pollination) (Hirsinger
1985; Knapp 1993). As the only species native to the U.S., C.
viscosisima and its phenotypes should be well adapted (Graham 1989).
The biggest barrier (seed shattering) has been partially eliminated due to the
discovery, under experimental conditions, of a natural mutation within C.
lanceolata x C. viscosisima hybrids that has exhibited significantly
reduced shattering (Knapp 1993). The non-shattering trait has been inherited
and reproduced over several generations. Additional recent key developments
include the development of lines that are both non-sticky and non-shattering,
as well as lines that are both auto-fertile and non-shattering (Knapp et al.
The genus Cuphea contains about 250 wild species native to Mexico,
Central, and South America (Graham 1988, 1989). Although C. viscosisima
is the only species native to the U.S., four introduced species exist in the
wild. A fairly large number of cuphea species have seed oils that are rich in
capric, lauric, caprylic, myristic, or other medium chain fatty acids (MCFAs)
(Earle et al. 1960; Miller et al. 1964; Litchfield et al. 1967; Graham and
Kleiman 1985). MCFAs are used in several industrial, medical, and food
applications (Bach and Babayan 1983; Arkcoll 1988). Lauric acid is used in
large amounts mainly in detergent and soap products. Caprylic, capric, and
myristic acid are potentially very useful MCFAs in industrial or nutritional
applications (Knapp 1992).
Currently the U.S. MCT demand is entirely met by imports of coconut (Cocos
nucifera L.) and oil palm (Elaeis guineensis Jacq.) (Arkcoll 1988),
both of which contain high levels of lauric acid. From 1986 to 1988, annual
imports of palm and coconut oil were about 723,000 t to the U.S. and 995,000 t
to Europe (Mackie and Calhoun 1991; Knapp 1993). The supply (and price) of
tropical oils has been unstable due to variations in weather, agronomic
practices, and political climate in the main producing countries while demand
continues to rise (Mackie and Calhoun 1991; Carlson et al. 1992). Demand for
capric acid (present in some cuphea species and suitable for plasticizer and
synthetic lubricant formulations) is currently met from modified petroleum
sources (Thompson 1984; Hirsinger 1985; Carlson et al. 1992).
Cuphea research and development efforts in the U.S. currently include
categories I-III. No commercial hectarage is cultivated at this time.
Breeding and agronomic work is ongoing at Oregon State Univ., with product
development research at Procter & Gamble Co., Cincinnati, Ohio and the
Until recently the seed shattering trait of cuphea made yield estimates
difficult. Using either a modified cotton picker (vacuum) for shattering types
or combine for the best available non-shattering types, seed yields in Oregon
often ranged from 500-1500 kg/ha. Even so, the amount of seed loss suggests
that potential seed yield is well over 2000 kg/ha. The slightly warmer climate
in Medford, as compared to Corvallis, Oregon, has routinely resulted in more
vigorous vegetative growth for a number of Cuphea species. However,
recent seed yields of the C. viscosisima x C. lanceolata hybrids
have been much lower in Medford than Corvallis. The effects of moisture stress
during hot weather, including reduced growth and increased seed shattering,
have been observed, but yield reductions have persisted even under well-watered
conditions. Perhaps the improved hybrids are better suited to a slightly
cooler climate than were the wild species grown previously.
Using a coconut oil price of $453/t (FAO, 1994) and adjusting for the
differences in lauric acid content (75% lauric acid in cuphea oil vs. 50%
lauric acid in coconut oil) the value of cuphea oil would be $0.68/kg, or
$0.24/kg seed containing 35% oil. At that price a 1500 kg/ha seed yield would
be worth only $360/ha. However, as in the case of meadowfoam, the presence of
unusual fatty acids (caprylic, capric, and myristic) in addition to the common
(lauric), could add more value when used in new applications. This suggests
that the crop should also be developed as a source of these unusual MCFAs
rather than simply as a replacement for tropical oils (Knapp 1992, 1993).
It would be desirable to combine the auto-fertile, non-sticky, and
non-shattering traits into a single cultivar. Such a plant would allow a
single harvest operation, possibly with a swathing operation followed several
days later by threshing using a pickup-reel combine as is routinely used for
grass seed harvests. The plant's stickiness can cause major equipment
problems, especially if the crop is drought-stressed. However, the sticky
resin may provide the plant with a protection against insects, and its removal
may not be a completely positive development (Knapp 1993). As improved
cultivars are developed, cultural practices must be continually evaluated.
Research on product development must continue, especially in regards to the
array of MCFAs available from different cuphea species.
For the cuphea phenotypes closest to domestication, vegetative growth is
favored by warm to hot weather with sufficient moisture, but seed yield is
decreased under hot and dry conditions. The C. viscosisima phenotypes
would likely grow well in the midwest and northwest U.S., southern Africa,
southeastern South America, eastern and northern Australia, and much of Europe.
The key early development came out of the extensive USDA efforts of the late
1950s and early 1960s when many plant species were analyzed in a search for
novel compounds. Out of this effort it was first recognized that Euphorbia
lagascae (Spreng.), Euphorbiaceae, was unique among the 58 euphorbs tested
in that the seed oil contained high levels of vernolic (12,13
epoxy-cis-9-octadecenoic) acid. E. lagascae is a drought-tolerant
native of Spain whose seed contains about 45%-50% oil, of which 60%-65% is
vernolic acid (Kleiman et al. 1965; van Soest 1993; Vogel et al. 1993).
Earlier, two other euphorbs (Cephalocroton cordofanus and
Cephalocroton peuschelii) were shown to contain high levels of vernolic
acid (Bharucha and Gunstone 1956; Gunstone and Sykes 1961). However, because
they are both perennial shrubs their potential for cultivation was deemed less
than that of the annual E. lagascae (Earle 1970).
The major problem with euphorbia that has hindered both breeding and agronomic
research has been its violent seed shattering habit, making it difficult both
to harvest and to measure seed yield. No wild accessions of euphorbia have
contained a non-shattering trait (Vogel et al. 1993; Pascual-Villalobos et al.
1994). Recently, chemically induced, non-shattering mutants were developed in
Spain (Pascual and Correal 1992; Pascual-Villalobos et al. 1994;
Vernolic acid, the C:18 epoxy fatty acid (EFA) found in the seed oil of E.
lagascae, would be useful in the paint and coating industry as a drying
solvent in alkyd resin paints, a plasticizer or additive in polyvinyl chloride
(PVC) resins (Riser et al. 1962; Carlson et al. 1981; Carlson and Chang 1985;
Perdue 1986), and possibly in pharmaceutical applications (Ferrigni and
McLaughlin 1984). Paints formulated with vernolic acid would greatly reduce
volatile organic compound (VOC) air pollution that now occurs with
volatilization of alkyd resins in conventional paints (Reisch 1989; Brownback
and Glaser 1992; Anon. 1993). The Clean Air Act amendments of 1990 require the
reduction of VOC pollutants, and regulations in California have been
implemented earlier with greater effect upon the paint industry (Reisch 1989;
Very few plants naturally produce high levels of vernolic acid in their seed
oils (Kleiman 1990) and most of those that do have significant barriers to
domestication and agronomic production (Earle 1970). The three species that
appear to have the best chance for domestication include Euphorbia
lagascae (Kleiman et al. 1965),Vernonia galamensis (Carlson et al.
1981; Perdue et al. 1986), and Stokes aster [Stokesia laevis Hill
(Greene)] (Earle 1970; Campbell 1981).
Current sources of EFAs include epoxidized soybean oil, linseed oil (from
oilseed flax), and processed petrochemicals (Carlson and Chang 1985; Perdue et
al. 1986; Dierig and Thompson 1993). However, epoxidation of simple vegetable
oils is an expensive process, and petrochemicals are a non-renewable and
increasingly imported raw material. The U.S. currently uses about 18,000 t of
EFAs in 1.2 billion liters/yr of paints and coatings alone (Reisch 1989; Anon.
Euphorbia research and development efforts in the U.S. currently include
categories I-III, while research in Europe (especially Spain) has mainly been
in categories I-II. There is no commercial hectarage at present. EFA product
development is ongoing at the USDA-NCAUR and at private companies.
Four selection lines originating from the Spanish non-shattering mutants were
grown for one year (1993) in Corvallis, Oregon. Seed yields in Corvallis were
low, probably due to plant immaturity at the onset of cool, wet weather in the
fall, but the non-shattering trait had persisted for the first generation. In
1994, four small, unreplicated, two-row plots were grown in Medford, Oregon
using seed harvested in Corvallis. Plant growth was vigorous, and most plants
were mature and beginning to senesce by early Oct. when they were carefully
harvested by hand onto plastic tarps and dried indoors. Seed shattering was
minimal, and calculated seed yields ranged from 1060 to 2800 kg/ha.
In 1995, using seed harvested in 1994, about 0.4 ha of euphorbia was grown in
Medford in replicated plots including row spacing and harvest method variables.
Unlike previous years, however, many plants were experiencing some degree of
shattering by early Sept. Plots were either cut with an International 201
swather (draper type) or sprayed with diquat to dry the stems to allow direct
combine threshing. Once dry, the euphorbia was combined in the field with a
Hege 125C plot combine. Plot yields in 1995 ranged from 115-600 kg/ha.
Differences were undoubtedly due to a combination of effects, including
increased amount of seed shatter, use of field machinery, field drying, larger
plots with minimal border effects, reduced irrigation in 1995, or other unknown
factors. Based on the 1994 yields and observations of seed set in 1995, it is
not unreasonable to believe that euphorbia could yield over 2000 kg/ha seed if
breeding and agronomic problems were solved.
It has been observed in Europe that the percentage of vernolic acid in
euphorbia seed oils varies little for different planting and harvest dates, or
by differences in accession or environment (van Gelder et al. 1993; Vogel et
al. 1993). This suggests that seed yield is a good predictor of fatty acid
yield, and cultural practices developed to achieve maximum seed yield should
also result in maximum fatty acid yield.
Average monthly prices for U.S. soybean oil ranged from $0.31 to 0.86/kg
between 1982 and 1994 (Knight-Ridder Financial 1995). Based on a soybean oil
price of $0.50/kg, and the value doubling or tripling after coversion to an EFA
(Perdue et al. 1986), euphorbia oil would be worth $1.00 to 1.50/kg oil, or
$0.50 to 0.75/kg seed. This value range was confirmed in a discussion with
industry personnel. At $0.60/kg seed and 1500 kg/ha seed yield, the gross
return to the farmer would be $900/ha. Of course, if euphorbia could be grown
with reduced input costs, especially irrigation, its net return to the farmer
would be greater than other crops having similar gross returns.
Although the seed shattering trait has made progress on euphorbia difficult,
availability of the non-shattering trait should prove to be very useful in
breeding. Other characteristics present in some Spanish mutants would also
increase seed yield, and could prove useful in breeding programs. Some mutants
had four or five seeds per pod, instead of the three per pod observed with wild
types (Pascual and Correal 1992; Vogel et al. 1993). While euphorbia's
mainstem crown normally has three main terminal branches, some mutants in Spain
had up to nine main terminal branches per mainstem crown, resulting in a
greater number of inflorescences. Plants with such "mobheads" had shorter
mainstems, possibly resulting in greater lodging resistance, and also may be
more determinate in seed maturation (Pascual-Villalobos, 1996).
Breeding work has barely begun with euphorbia, but the availability of the
non-shattering trait appears to be a breakthrough that can be exploited.
E. lagascae is highly self-fertile, with pollen transfer occurring
before insects can access the floral organs (Vogel et al. 1993). Therefore,
outcrossing should be limited. Agronomic requirements of this crop have not
been quantified, but now can be evaluated using non-shattering lines. Areas
needing study include water and fertility requirement, planting and harvesting
techniques, and seed cleaning and processing. Weed control research is also
necessary, although some preliminary evaluations of potential herbicides have
been made (Vogel et al. 1993). Due to the presence of latex and other
potentially irritating compounds in the stems and petioles, it will be
important to understand which safety precautions are necessary during harvest
and processing. Processing chemistry and product development should continue
on a larger scale as more seed becomes available.
Euphorbia requires a long season for maximum seed production. It has appeared
to be very tolerant to drought and heat (although the effect on yield is not
known). Likely areas for production include much of the western U.S., northern
Africa, southern Europe, northwest Argentina, and southern and western
Australia. It should be able to compete well in situations where irrigation
water is expensive or unavailable.
The investigation of Vernonia anthelmintica (L.) Willd., Asteraceae, by
Gunstone (1954) was the first report of a natural epoxy fatty acid in a seed
oil (Earle 1970). As part of the extensive USDA efforts of the late 1950s and
early 1960s to analyze many plant in search of novel compounds, it was
confirmed that V. anthelmintica contained high levels of vernolic acid
(Smith et al. 1959). Following that, a number of other Vernonia species
were examined (Earle 1970). For a time, V. anthelmintica seemed to be
the species with the greatest potential for domestication, and quite a bit of
agronomic and utilization research was performed (summarized by Perdue et al.
1986). However, poor seed retention remained a major barrier to domestication.
During late 1966 and early 1967, C.E. Smith Jr. collected some vernonia seeds
in Africa from plants later identified as several sub-species of Vernonia
galamensis [Cass.] Less. (Smith 1971). These contained about 30% oil, of
which up to 78% was vernolic acid. A plant exploration trip to Africa by R.E.
Perdue, Jr. in 1964 resulted in collection of seed from impressive mature
plants that was later identified as a sub-species of V. galamensis
different than that collected by Smith (Perdue et al. 1986). This seed
contained about 42% oil, of which about 73% was vernolic acid (Carlson et al.
1981). Thus, this wild germplasm contained roughly 30% more vernolic acid than
the best improved V. anthelmintica cultivars (Princen 1979). Based on
the higher oil content, its observed seed retention, seed density, and seed
size in the wild, it appeared V. galamensis had the greater potential
One initial problem that discouraged domestication at temperate latitudes was
short-day flowering requirement and frost intolerance. Thus, at temperate
latitudes, the short days required for flowering were rapidly followed by
freezing temperatures, preventing seed production (Perdue 1988; Phatak et al.
1989). A major breakthrough was the discovery that one accession of V.
galamensis subsp. galamensis var. petitiana (Gilbert 1986)
was day-neutral in flowering habit (Dierig and Thompson 1993) and auto-fertile.
The day-neutral flowering habit has been retained by several generations of
hybrids (Dierig et al. 1995). Although var. petitiana has several
agronomic shortcomings, a breeding and selection program using hybrid crosses
with var. ethiopica (which exhibited good plant vigor, large seed heads,
large seeds, and good seed retention) has been ongoing with cooperators
(including the author) in several states. Results suggest that further
selection could result in vernonia hybrids that produce economically viable
yields in several locations in the continental U.S. (D. Dierig 1995, pers.
Seed oil of V. galamensis contains large amounts of vernolic acid
(Perdue et al. 1986), an epoxy fatty acid identical to that found in euphorbia.
However, about 45% of the vernolic acid in vernonia is in the trivernolin form,
more than double that of euphorbia or stokes aster (Tallent et al. 1966; Earle
1970; Plattner et al. 1978; Carlson et al. 1981). For some applications this
richer trivernolate content in vernonia may impute greater value than the
vernolic acid from euphorbia or Stokes aster. In general, the product
applications would be identical as those discussed for euphorbia.
Competing sources for EFAs found in vernonia would be essentially the same as
those listed for euphorbia.
Vernonia research and development efforts in the U.S. currently include
categories I-III. No commercial hectarage is currently grown in the U.S.
Small hectarage crops have been grown in Africa and South America using wild
types to produce oil for analysis and processing research as well as improving
agronomic knowledge (Anon. 1993; Carlson et al. 1992). Approximately 30% of
vernonia's seed weight is vernolic acid, as in euphorbia. As such, the crop
would have equivalent value, assuming extraction and processing requirements
were similar. Reported seed yields in Africa using wild types have been as
high as 2000 kg/ha, although details of experimental conditions have been
limited. Day-neutral hybrids tested at several temperate North American sites
in 1994 yielded between 166 and 1200 kg/ha (D. Dierig 1995, pers. commun.). If
a seed yield of 1500 kg/ha were realized, the gross return to the farmer would
be $900/ha at a value of $0.60/kg seed (the same as euphorbia). Involvement by
USDA and university scientists, private industry, and the coordination of crop,
processing, and product research has increased the chances for successful
domestication of vernonia.
While vernonia exhibits a dense canopy and thus competes well with weeds once
it is established, early season weed control techniques will be essential
during the seedling and early vegetative stage. Field tests have identified
several herbicide compounds that should prove useful in vernonia cultivation
(Roseberg 1996b). Seed retention and yield both need to be improved for
vernonia to be commercialized. Ongoing breeding and selection programs
increase the chances of improving these traits. Many questions regarding
vernonia's agronomic requirements remain unanswered, including planting, water,
fertilizer, and harvesting. Further evaluation and registration of herbicides
or alternate weed control strategies is required. Some vernonia plants also
suffer from a "sudden death syndrome," whereby an entire individual plant, at
any growth stage, will wilt, senesce, and die, sometimes within a matter of
hours. This has been observed at several locations in the U.S., and does not
seem to be correlated to hybrid or management practice. It is assumed these
are bacterial, fungal, or viral attacks, but a pathogen has not been positively
identified. Worker safety during harvest and processing needs to be better
understood due to the types of oils present in vernonia. Seed processing and
product development research should continue in order to utilize vernonia's
seed oils effectively.
Vernonia seems to prefer well drained soil. It is also fairly drought tolerant
once established, and requires a long season for maximum seed set. Production
areas would likely include much of the temperate U.S., south and east Africa,
parts of Argentina and southern Australia. Improved day-neutral cultivars
would be required in all but the upland tropical areas of Africa and possibly
parts of South America.
Several species of the genus Grindelia produce a diterpene resin
(grindelic acid) and other resinous compounds on the surface of their flowers,
leaves, and stems (Guerreiro et al. 1981; Bohlmann et al. 1982; Timmermann et
al. 1983). Grindelia camporum (Greene), Asteraceae, is a native of the
western U.S., especially the central valley of California (Bailey 1976;
Hoffmann et al. 1984; Hoffmann and McLaughlin 1986). The identification of
grindelic acid as an important constituent of this resinous plant (Bohlmann et
al. 1982), came out of a previous examination of 195 plant species as to their
suitability for agriculturally derived crude oils in the arid southwestern U.S.
(McLaughlin and Hoffmann 1982), and was a key factor in the initial development
of this species. Diterpene resin acids constituted between 65 and 75% of the
total crude resin in the plant (Hoffmann and McLaughlin 1986; McLaughlin 1986a,
b). These diterpene acids have properties similar to wood rosin and its
derivatives, and form the basis for grindelia's economic crop potential
(Hoffmann 1985; Hoffmann and McLaughlin 1986). Studies on the heritability of
resin production indicate that genetic improvement is feasible (Dunford 1964;
McLaughlin 1986a, b; McLaughlin and Linker 1987). Glands on the surface of
flowers are responsible for most of the resin production, with little resin
produced on the stems or leaves (Hoffmann et al. 1984).
The diterpene resins from grindelia are very similar to those obtained by
grinding up stumps or tapping live old growth pine trees (Hoffmann and
McLaughlin 1986; Thompson 1990) and are known as "naval stores." They consist
of a large group of compounds, including turpentine, fatty acids, rosins, and
their derivatives (Thompson 1990) once used to calk ships, but now used in
paper sizing processes as well as producing rubber, chemicals, ester gums, and
resins for many applications (Hoffmann and McLaughlin 1986). U.S. consumption
of naval stores from old growth pine trees has been fairly static at about
500,000 t/yr (Hoffmann and McLaughlin 1986), but domestic production has almost
disappeared, as supplies of old growth stumpage has decreased and costs of
tapping the decreasing number of live trees has increased.
Grindelia research and development efforts in the U.S. currently include
categories I-II, with no commercial production. Grindelia camporum has
received the most interest in the U.S. due to its greater biomass production
compared to other resin-producing U.S. natives, such as G. squarrosa
(Pursh) Dunal., G. latifolia Kellogg, and G. stricta DC. (Bailey
1976; Ravetta et al. 1995). Recently, research has begun in Argentina using
G. chiloensis (Cornelissen) Cabr., a South American native that
exhibited a much higher resin content on a whole-plant basis (although lower
total biomass) than G. camporum (Bailey 1976; Guerreiro et al. 1981;
Ravetta et al. 1995). Large numbers of resin glands are found on the stems and
leaves of G. chiloensis (D. Ravetta, 1995, pers. commun.), whereas resin
glands occur mainly just on inflorescences of G. camporum (Hoffmann et
al. 1984; Hoffmann and McLaughlin 1986).
In Arizona, experimental tetraploid lines of G. camporum have yielded up
to 12.5 t/ha biomass per year, with a crude resin content of up to 11%,
resulting in annual crude resin yields of up to 1.2 t/ha, using between 57 and
75 cm of irrigation water (Hoffmann and McLaughlin 1986; McLaughlin and Linker
1987). In more recent Arizona tests, G. camporum single plant biomass
yields were about twice that of G. chiloensis, although resin content
was about two-thirds higher for G. chiloensis (Ravetta et al. 1995).
In southern Oregon, plantings were made in 1992 and 1993 at two locations, one
a deep sandy loam and the other a moderately deep cracking clay. In 1993
plants grown in the sandy loam yielded an oven-dry biomass average of 35.2
t/ha, vs. 6.8 t/ha in the clay. Analysis of the separated flower, leaf, and
stem fractions resulted in an overall average resin yield of 3.70 t/ha in the
sandy loam and 0.85 t/ha in the clay. In 1994 the same plantings yielded an
oven-dry biomass average of 30.4 t/ha in the sandy loam vs. 28.3 t/ha for the
clay, and an overall average resin yield of 4.42 t/ha in the sandy loam and
1.66 t/ha in the clay. In these experiments, the resin yield for flowers alone
ranged from 11.6% to 26.6% on an individual plant basis, with immature flowers
generally having higher resin content than mature flowers. Resin content of
leaves ranged from 9.2% to 21.0%, stems ranged from 1.4% to 3.6%, and combined
stems with leaves ranged from 3.3% to 7.3%. Resin content was much higher in
all plant parts for plants grown in the clay soil in 1993, but the opposite was
true in 1994. Due to different irrigation rates, water stress was greater in
the clay in 1993, but greater in the sandy loam in 1994, which may have
contributed to the observed differences in yield and resin content between the
two sites and years. In natural sites, grindelia's preference for soils higher
in clay content (S. McLaughlin 1992, pers. commun.) may be due to the greater
water holding capacity of the soil in xeric climates rather than a preference
for the drainage or texture of a clay soil per se.
Grindelia seed germination is enhanced under light and is optimum at 10deg. to
20deg.C (McLaughlin and Linker 1987; R. Roseberg unpub.). Dates of
transplanting and planting density effects on biomass and resin yield, crop
growth rates, and water use efficiency have been examined by McLaughlin and
Linker (1987). Growth and yield data from Oregon and Argentina (D. Ravetta
1995, pers. commun.) indicate that grindelia may be better adapted to dry areas
that are somewhat cooler than Arizona, and that plants with high biomass yields
can also have high resin content.
One factor that favors growing domesticated industrial crops in place of some
traditional food crops is that their raw materials (such as resins, gums, and
waxes) have typically been more valuable than food on a unit weight basis
(McLaughlin 1985). Resins similar to those found in grindelia rose in price
from $0.59/kg in the late 1970s to $1.10 by the mid 1980s (Hoffmann and
McLaughlin 1986). While rosin prices hit a low in 1993 (Gallagher 1994a),
prices have increased since then due to reduced supply and increase demand
(Santos 1994; Gallagher 1994b). The increased demand for fine paper for
ink-jet, laser-jet, and copier applications as well as increased use of
recycled paper have increased demand for paper sizing chemicals, including
rosin (Killy 1994).
If grindelia resin were valued at $0.60/kg, a biomass yield of 30 t/ha with a
crude resin yield of 3.0 t/ha would be worth $ 1800/ha. Due to resin
extraction and processing costs, farm gate values for raw material would be
estimated at 50%, or $900/ha. Reduced input costs would contribute to a
farmer's net return from a grindelia crop, mainly due its presumed reduced
irrigation requirement compared to other crops. Because grindelia is a
perennial, establishment costs would be reduced, further adding to a farmer's
net return. Thus, the return could prove attractive in areas where other crops
were limited without large inputs of expensive irrigation water.
Resin yields need to be increased to improve grindelia's economic feasibility
(Hoffmann 1985; Hoffmann and McLaughlin 1986). Genetic analysis and
preliminary selection trials indicate an increase to 15%-20% resin content is
possible (McLaughlin 1986a, b). Areas of highest adaptation for G.
camporum need to be identified. The high concentration of resin ducts on
all parts of the G. chiloensis plant suggest that this species could be
domesticated in adapted areas. Also, research in Argentina with interspecific
crosses of grindelia species is underway to combine the biomass production of
G. camporum with the ubiquitous resin gland morphology of G.
chiloensis (D. Ravetta, 1995, pers. commun.).
Many agronomic requirements of grindelia and their effects on yield and resin
production are still unknown. Results in Oregon suggest the possibility of
achieving high biomass production without dramatically decreasing resin
content. However, the plant's resinous nature could make harvest with standard
cutting equipment difficult. Processing procedures also need to be developed.
Product development using grindelia biomass as a raw material also is necessary.
Grindelia is likely suited to areas that are dry and warm. Deep soils would
decrease the need for irrigation, as would presence of some clay. It is frost
tolerant and a perennial, making it useful in temperate climates. Likely areas
would include western U.S., western Australia, northern Africa, southern
Europe, central China, and southern areas in South America.
Interest in hesperaloe (Hesperaloe funifera [Koch] Trel., Agavaceae)
arose from a recent study of the fiber properties of several agaves, including
hesperaloe, that are native to the southwestern U.S. and northern Mexico
(McLaughlin and Schuck 1991). Hesperaloe leaves contained fiber cells that
were both longer and narrower than those of sisal, and compared favorably with
wood and non-wood fiber species for specialty paper applications. It had been
noted that native peoples had cultivated H. funifera as a source of hard
fibers (Trelease 1902; Dewey 1943) and several agavaceous species were already
traded internationally due to their fiber quality, including sisal, henequen
(Agave fourcroydes Lem.), and New Zealand flax (Phormium tenax
J.R. & G. Forst.). It was assumed that species native to the arid
southwest would be very drought tolerant. Finally, the value of pulp from hard
fiber plants has typically been much higher than softwood pulps (Baker 1985;
The first agronomic studies of Hesperaloe funifera were performed in
Arizona. In addition to growth and yield data, preliminary information on
water use, soil fertility requirements, regrowth yields and time requirements,
and economic analysis were developed (McLaughlin 1993a, b, 1995).
Determination that H. funifera was a crassulacean acid metabolism (CAM)
plant further bolstered the observations of drought tolerance (Ravetta and
McLaughlin 1993). Preliminary studies on floral biology have given insight
into improved strategies for breeding and seed production (Ravetta and
Hesperaloe produces hard fibers in the leaves that are very long, thin, and
strong when compared with wood fibers, bast fibers, and even other hard fibers
(McLaughlin and Schuck 1991; McLaughlin 1993a). Hard fibers have been
successfully used to make thin, high value, specialty papers requiring strong
tear resistance, such as are used in making currency, tea bags, filter papers,
and specialty books (Clark 1965; Corradini 1979).
Some of the world's important agricultural fibers are classified as bast
fibers, obtained from phloem cells of dicot stems such as flax, kenaf, jute,
ramie (Boehmeria nivea L.), and hemp. However, many important fibers
are classified as hard fibers, obtained from the leaves of tropical monocots,
such as abaca (Musa textilis Née), sisal, henequen, and New
Zealand flax. Unlike other fibers, hesperaloe fiber is naturally white, thus
eliminating the need for bleaching (Steve McLaughlin 1993, pers. commun.).
Hesperaloe research and development efforts in the U.S. currently include
categories I-II. There is no commercial hectarage of hesperaloe. Until very
recently all research plots have been small and located near Tucson, Arizona,
but there are research plantings of several hectares at Maricopa, Arizona
(McLaughlin 1995), and a small observation trial was planted near Medford,
In Arizona, hesperaloe biomass accumulated to between 20 and 77 t/ha fresh
weight after three years, depending on stand density (McLaughlin 1993a) and
after five years of growth, yields increased to between 87 and 192 t/ha, again
depending on stand density (McLaughlin 1993b). Under very good conditions,
fresh weight yields in Arizona could reach about 200 t/ha (20 t/ha dry fiber)
after five years (McLaughlin 1995). The growth rate accelerated after
development of lateral rosettes (hesperaloe's growing point), which occurred
mostly during the fourth year. Thus biomass accumulation after five years was
greater than the sum of two harvests at three and five years (McLaughlin
A small planting in southwest Oregon was started in 1992 and expanded in 1993
and 1994, to observe whether hesperaloe would survive cool, low light
conditions during winter. Survival has been good for the 1993 and 1994 plants,
with rodent damage during the dry summer causing more serious problems than
winter weather. Growth, however, has been slow in Oregon. Yields after three
years, estimated using the non-destructive technique developed by McLaughlin
(1993a), were 9 t/ha (fresh weight) at densities of about 27,000 plant/ha,
compared to 77 t/ha observed in Arizona. About 50% of the total biomass was
added during the third year in the Arizona trial, while 90% was added during
the third year in Oregon. Thus during the first and second years, survival is
the main issue for hesperaloe in cooler, non-native areas. Whether or not the
increased growth in subsequent years is enough to justify growing the crop will
depend on relative value and return from other uses of the land.
Crop value for hesperaloe is very difficult to estimate until processing
procedures are developed. However, preliminary market analysis suggested a
potential processed value of $400-600/t dry fiber, corresponding to $40-60/t
fresh weight (McLaughlin, 1993a). At $50/t fresh weight, a third year harvest
in Arizona of 77 t/ha would be worth $3850/ha, and a fifth year harvest in
Arizona of 200 t/ha would be worth $10,000 once processed. Processing costs
could decrease the farm gate price to 50% of the processed fiber value, and
until a market is developed, only crude estimates of crop price and value are
Although hesperaloe produces a high quality fiber, decortication of the leaves
to produce dry, clean fiber has been difficult (McLaughlin 1995). There have
been preliminary studies of hesperaloe genetics (Pinkava and Baker 1985;
McLaughlin 1996), but the perennial habit of hesperaloe necessitates long-term
efforts for breeding as well as agronomic studies. Its slow growth rate,
especially in the first two years, makes weed control difficult on a large
scale (S. McLaughlin 1995, pers. commun.). The range of adaptation is still
unknown. The prospects and progress of hesperaloe domestication are discussed
in more detail by Steven McLaughlin elsewhere in this volume.
Hesperaloe funifera is found in the wild at low elevations in the
east-central part of the Chihuahuan Desert in Coahuilla and Nuevo Leon, Mexico.
H. nocturna Gentry, a species that produces similar fibers, is a native
of the Sierra Madre Occidental area of northeastern Sonora, Mexico (McLaughlin
1993a; Ravetta and McLaughlin 1993). Based on research to date, hesperaloe
production would seem limited to hot and dry locations near existing paper
facilities, where its drought tolerance and high value fiber would make it
competitive. The range of adaptation is still unknown, but its survival in
southwest Oregon was somewhat surprising. Growth and yield is probably
inadequate at higher latitudes, but there may be situations where it could be
grown outside of Arizona and Mexico in locations less suited for conventional
crops. Likely production areas include parts of the western U.S., Mexico,
northern Africa, and western Australia. In any location, first year survival
is the key to success, after which its perennial nature and regrowth from
rosettes after cutting are advantageous.
Hemp (Cannabis sativa L., Cannabaceae) has been grown in some parts of
the world since ancient times, and it produces a high quality fiber (Dempsey
1975). Research programs have been most active recently in Europe, and
production is a reality in eastern Europe and France (van Soest 1993).
Restrictions on cultivation and research in the U.S. have been due to the
potential for illegal drug production (marijuana). However, selections with
low cannabinol levels have been developed (van Soest 1993), which may help
decrease this problem. Progress in commercial production of hemp pulp for
specialty papers in Europe is discussed by Anthony Capelle in more detail
elsewhere in this volume.
Sunn hemp (Crotalaria juncea L., Leguminosae) produces a bast fiber,
similar to kenaf, that could be readily used in pulp and paper applications
(Dempsey 1975; Cook and White 1995). Unlike kenaf, it is highly resistant to
root-knot nematodes and thus can be grown in some areas where kenaf cannot
(Cook and White 1995). Sunn hemp is fairly drought tolerant, can grow in
marginal soils, and, being leguminous, has low nitrogen requirements. Sunn
hemp is discussed by Charles Cook in more detail elsewhere in this volume.
Various heavy metals may be present in soil naturally as well as due to mining
or industrial operations, and areas of high metal concentrations occur
throughout the U.S. (Holmgren et al. 1993). There are certain plants that
"hyperaccumulate" various heavy metals such as Cd, Co, Cr, Cu, Mn, Ni, Pb, or
Zn from the soil, taking them up in very large amounts that are unrelated to
any known physiological need. Excellent summaries describing many
hyperaccumulating species, representing several families, were written by Baker
and Brooks (1989) and Baker et al. (1994a). A large number are in the
Brassicaceae family, including Thlaspi and Alyssum species. Dr.
Rufus Chaney of the USDA-ARS Environmental Chemistry Laboratory in Beltsville,
MD, has examined numerous species regarding their heavy metal hyperaccumulation
potential (Comis 1995). Some of these plants are very small and do not have
any agronomic potential, except that this trait might be transferred to more
agronomically suitable species. However, some of these plants are large enough
that they aleady have potential as "biomining" crops, such as Alyssum
tenium Halacsy and Dichapetalum gelonioides (Bedd.) Engl. subsp.
tuberculatum Leenh. (Dichapetalaceae) for nickel, and possibly alpine
pennycress (Thlaspi caerulescens, J. & C. Presl.) for Cd, Zn, and Pb
(Homer et al. 1991; Baker et al. 1994a, b). Such crops would be valuable in
reclaiming tailings from traditional mining operations, but also in mining the
metal directly from naturally enriched soils, allowing the metal to be
extracted from the crop biomass after cutting and ashing. This approach has
the potential of allowing mining of heavy metals to occur in a more
environmentally friendly way (Chaney 1983; Baker et al. 1994a; Comis 1995).
As an example, there are serpentine soils containing high concentrations of
nickel in parts of southwestern Oregon and northwestern California, a region
containing the only commercial Ni smelting operation in the U.S. (Helgerson and
McNabb 1985). If one could grow a perennial bushy plant producing 40 t/ha
biomass annually that contained 2% Ni, the metal yield would be 0.8 t/ha. At
$7.00/kg, the refined value of the Ni would be $5600/ha (R. Chaney 1994, pers.
commun.). Although processing and refining costs would be considerable (as
they are in conventional mining operations), the potential to produce a crop in
unproductive heavy metal-affected soil or even decontaminating mine spoils
would provide a double benefit both to farmers and the environment.
There are many plants that naturally produce valuable and interesting compounds
with potential industrial applications. An excellent overview of several of
them was given by Robert Kleiman at the Association for the Advancement of
Industrial Crops annual meeting in Catamarca, Argentina, during Sept., 1994.
Those plants included: Stokes aster, Dimorphotheca pluvialis (L.)
Moench; Crepis biennis and C. alpina; coriander (Coriandrum
sativum L.); Calendula officinalis L.; and money plant (Lunaria
annua L). Their development awaits the coordinated efforts of crop
production, processing, product development, and marketing before domestication
will become a reality.
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